Money and Exchange rates

Transcription

1 Macroeconomic policy Class Notes Money and Exchange rates Revised: December 13, 2011 Latest version available at So far we have learned that monetary policy can affect the interest rate and output in the short run and that in the long run it does not affect real interest rates nor output but it affects prices (long run money neutrality). Now we will focus on the effects of monetary policy on the international variables focusing in particular on exchange rates. Real and Nominal Exchange Rates We usually refer to two types of exchange rates: real and nominal. The nominal exchange rate is just the price of a currency (i.e. of the piece of paper issued by the central bank of a given country) in terms of another. In other words the exchange rate tells me how many units of foreign currency can I get with a unit of my currency. When we say that the exchange rate of the Canadian dollars relative to US dollar is 1.5 we mean we get 1.5 Canadian dollars with 1 US dollar. We say that dollar depreciates when we get less foreign currency with a dollar and appreciates when we get more foreign currency with a dollar. The real exchange rate on the other hand is just the relative price (expressed in the same currency) of a particular good or basket of goods in two countries. This tells how many foreign goods can we get with a given American good. An example of that is how many Prada suits can I buy in Italy with the value of the same suit made in US by Calvin Klein. A possible way of measuring this is to sell my CK suit, exchange my dollar revenue in euros and then compare the sum with the price of the Prada suit. For example if the price of a CK suit in US is 1000$ and the exchange rate between dollar and euros is 0.8 I get 800 euros from selling the CK suit. If the price of a Prada suit in Italy is 400 Euros this means I can buy 2 Prada suits in Italy with the value 1 CK suit in US, or that the real exchange rate for suits is 2. In this

2 Exchange rates 2 example American suits are more expensive than Italian suits so Italian suit makers are going to be more competitive on the world markets. So the real exchange rate is also a measure of competitiveness. Most often instead of focusing on a single good we focus on the price of an aggregate of goods (like the basket that compose the CPI) so the real exchange rate is computed as rx = P e P where P is the domestic general price level, e is the nominal exchange rate and P is the foreign price level. Consider again the case of US versus Europe. If the US real exchange rate goes up is either because P (American prices) goes up, or because e goes up (the dollar appreciates) or because P goes down (the euro prices go down) In all these cases we observe an increase in competitiveness of European goods relative to US goods. Often also instead of just the real (or nominal) exchange rate with one country statistics report the value of the dollar against a group of currencies or the value of the American goods versus the rest of the world goods. Figure 1 plots the nominal exchange rate and of the real exchange rate of the dollar versus a broad group currencies. Purchasing power parity as an exchange rate theory Figure 1 reveals that nominal exchange rate fluctuates a great deal and can have long run trends. The purchasing power parity theory can provide us some guidance on the directions of these fluctuations, in particular the long run trends. The dollar price of a basket of goods and services in US is P US The dollar price of a comparable basket abroad is P /e where e is the number of foreign currency units that I can get for a dollar (so e is the strength of the dollar). Purchasing power parity says that the nominal exchange rate should adjust (because arbitrage in goods market) so that costs are equalized across countries. The equalization of costs implies that or P US = P /e P US e/p = rx = 1 (1) that is it implies that the nominal exchange rate should move so to keep the real exchange rate constant. Suppose for example that we start in a situation of purchasing power parity (rx = 1) and that foreign prices go up 10% while US prices are constant. If the exchange rate does not move US goods will be cheaper and foreigners will rush to buy them; to buy US goods foreigners will need to exchange their currency for dollars, driving up the price of the dollar (e goes up) until purchasing power parity is restored. Obviously purchasing power parity does not hold in the short run (just

3 Exchange rates Dollar nominal exchange rate Dollar real exchange rate

4 Exchange rates 4 observe the second panel in figure 1 that shows large fluctuations in the real exchange rate) so the theory does not help us to predict day to day movement in the exchange rate (one of the many reasons why the theory does not hold is the presence of non tradable goods, or trade restrictions that reduce the possibility for arbitrage). Notice though that in the long run the real exchange rate reverts toward a constant mean, while the nominal does not, indicating that the theory is somehow helpful in predicting long run changes in the nominal exchange rate. For example, figure 1 suggests that the reason why the dollar has appreciated against the foreign currencies has been foreign prices increasing more than US prices. Along these lines the PPP theory, in conjunction with the quantity theory of money, is helpful in understanding the long run impact of money expansion on exchange rates. In particular consider taking logs and time differences of equation 1 one gets log(e t+1 ) log(e t ) = (log Pt+1 log Pt ) (log Pt+1 US log Pt US ) = π t π t suggesting that the change in exchange rate between two countries should be related to the relative inflation in those 2 countries, where higher inflation leads to more depreciation. The quantity theory teach us that hence we get π t = g M g Y π t = g M g Y log(e t+1 ) log(e t ) = g M g Y g M + g Y (2) Equation 2 connects the PPP theory with the quantity theory of Money to provide a long run theory of the evolution of the nominal exchange rate. If, for example, US expands its money supply more than its foreign partners the quantity theory predicts that US prices should grow more than foreign prices. But if in the long run the real exchange rate between US and Europe is constant (PPP) it must be that the nominal value of the dollar falls (log(e t+1 ) log(e t ) <0) so US money expansion causes depreciation of the dollar. Similarly should US experience faster real growth than its partners, US should see an appreciation of the nominal exchange rate, because a faster growth would increase the world demand for dollars. This effect is very visible in the case of very rapid price changes (for example hyperinflations): countries that experience rapid price changes also experience rapid depreciation, so that their real exchange rate does not change much. Next we will try to understand the short run behavior of exchange rates and to do so we need to discuss explicitly exchange rate policies. Exchange rate regimes A large number of countries (including US) follow a policy of floating exchange rates, that is they leave the markets to determine the equilibrium value of the their currency

5 Exchange rates 5 against other currencies. Some other countries let the exchange rate float but they intervene on the foreign exchange market (buying or selling their own currency) from time to time to limit exchange rate variability: such policies are called managed floating exchange rate or dirty floating. Other countries decide to peg the exchange rate of their currency against some other currency (for example the dollar). Pegging the exchange rate means that the Central Bank stands ready to exchange dollars for the local currency and local currency for dollars at a fixed value. We distinguish between moving (or crawling) pegs in which the target value for the change rates changes over time and frozen pegs in which the target exchange rate does not change. An example of moving peg is China now, it has been Brazil before the 1999 crisis, with a moving target for the value of the local currency relative to the dollar, or Turkey before the 2001 crisis, that had a target of scheduled devaluations of its currency against a basket of currencies. An example of a frozen peg was Argentina in the 1990s. There the Central Bank stood ready to exchange one dollar for one unit of local currency since In order for the frozen peg to be credible the bank must have enough dollars to satisfy any possible demand. Notice that there is important difference between dollars and local currency: local currency can be printed by the local central bank but dollars cannot, so a central bank can run out of dollars. In order to implement a credible frozen peg countries have adopted an institution called currency board: under a currency board any new unit of foreign currency that is issued has to be backed by a dollar in the vaults of central bank. In this case the bank will never run short of dollars and will be able to satisfy the demand of people wanting to exchange local currency for dollars. Example of currency boards are Argentina in the 1990s and Hong Kong. A more extreme way of fixing exchange rate is to give up the domestic currency altogether. This can be done in two ways. One possible way is to form a monetary union (that is what happened in Europe). The currencies of the single countries will be replaced by a single currency so that there will be no longer issues of exchange rates like there are no issues of exchange rate between the dollar in California and the dollar in Minnesota. The other possible way is the so called dollarization. This is what happened in Panama long time ago and recently in Ecuador: the central bank goes out of business and people just use dollars for every transaction. There is an important difference between dollarization and currency (or monetary) unions. In a currency union the countries in the union give up their monetary independence but they have some control over the central monetary authority that should act on behalf of all members of the union. So in the case of Europe for example the European Central Bank will not solely act on behalf of the French interest but French will have some say on the European monetary policy. Dollarization on the other hand is a unilateral decision and the country that dollarizes has and expect to have no control whatsoever over the supply of dollars. The table below summarizes the possible exchange rate regimes.

6 Exchange rates 6 Exchange Rate Regimes Floating Managed Floating (Target Zone) Moving Peg Frozen Peg (Currency Board) Monetary union Currency Abandonment (Dollarization) Monetary policy under fixed exchange rates Fixing the exchange rate imposes a constraint on monetary policy. This is apparent if one thinks of dollarization: by giving up his own currency the country clearly gives up monetary policy as well. Also in the case of a currency board the constraint is pretty clear because by law the central bank cannot print and inject the local currency if they don t have dollar reserves to back the liquidity. If a country decides to fix the exchange rate without adopting a currency board (as in the case of Mexico) the constraint come from the fact that if the central bank prints too much money the country is subject to speculative attacks that can force the country to abandon the policy of fix exchange rate. In order to understand this concept is useful to analyze the balance sheet of a central bank (for example the Central Bank of Mexico) who tries to peg the exchange rate of the Peso to the dollar to the value of 1 (one peso for one dollar) Assets ( 000) Liabilities ( 000) Foreign exchange Reserves $100 Currency = P 1000 the previous balance sheet shows that if the bank is not under a currency board the outstanding amount of currency can be higher than the amount of foreign reserves. But suppose now that agents in the market start believing that the peso will be devalued (so one dollar will exchange for two pesos); then it is convenient for them to exchange their pesos for dollars to realize a capital gain. They will start to do so until the central bank finishes the reserves: at that point the balance sheet of the central bank will look like Assets ( 000) Liabilities ( 000) Foreign exchange Reserves $0 Currency = P 900 at this point the central bank will no longer be able to exchange dollar for pesos so the exchange rate cannot be maintained fixed and the peso will actually be devaluated.

7 Exchange rates 7 Clearly if the amount of outstanding currency is always less or equal than the foreign exchange reserves (as in the currency board) there is no possibility of an attack because the speculators will finish the pesos before the bank exhaust the reserves. The problem with currency boards is that there are established by a law but there is no guarantee they will last forever so there is always the possibility that government decide to abandon them and then the exchange regime would collapse. Interest rates under fixed exchange rates Another way of seeing the fact that under fixed exchange rate a country loses its monetary independence comes from the interest rate side. Let s consider the case of Argentina and let s consider the FFR and the equivalent of the Federal Funds Rate in Argentina that is denominated in pesos(suppose that they are both free of risk of default) i P i $ e P/$ e e P/$ Interest rate on Peso funds Interest Rate on Federal Funds Peso Dollar rate (How many pesos you can get with a dollar today) Peso Dollar expected rate Let s now compare the return on two assets using the same currency (the dollar). Suppose the international investor is contemplating investing one dollar in a the federal funds or in Peso funds. If she invests in the federal funds her return will be Return on Dollar assets (in dollar) =(1 + i $ ). If she invests in pesos she will first need to exchange the dollar in pesos obtaining e P/$ marks then invest in deposits yielding a rate of (1+i P ) and then exchange back the marks into dollars at an expected exchange rate of e e P/$.Summarizing these operations we can write here expected returns as Return on Peso assets (in dollar)=(1 + i P ) e P/$ e e P/$ notice that this return is composed of two parts: the return on the Peso asset and the expected appreciation of the currency (this second part can be negative). The (uncovered) interest parity condition We will now determine the equilibrium in the foreign exchange market. We say that the foreign exchange market (between dollar and pesos) is in equilibrium when the

8 Exchange rates 8 expected return on dollar assets is equal to the expected return on peso asset that is Return on Dollar assets (in dollar) = Return on Peso assets (in dollar) (1 + i $ ) = (1 + i P ) e P/$ e e P/$ taking logs of the previous condition we also have i $ = i P + log(e P/$ ) log(e e P/$) i $ = i P Expected % peso depreciation to make things clear suppose that the interest rate on dollar assets is 6% and the one on peso rate is 10%. Suppose that the exchange rate today is 1 and that is expected to go to 1.05, that is the peso is expected to depreciate 5%. In this case the return on dollar assets will be 6% but the return on peso assets will be 10% - 5% = 5% so the left hand side of the parity above is higher than the right hand side. In this case dollar assets are a better options and everybody will try to sell pesos deposits and buy dollar assets. But this will tend to instantly depreciate the peso (raise e P/$ ) until the parity is restored. Now consider the case in which the exchange rate is fixed. In this case the expected exchange rate is equal to the current exchange rate (e P/$ = e e P/$ ) and therefore the parity above becomes simply i $ = i P this implies that the central bank of Argentina does not have any control on its interest rate but its interest rate has to be equal to the Federal Funds Rates that is actually decided by the FED. Figure 2 plots Argentina s interbank rate against the Federal Funds rate during the period in which Argentina had fixed exchange rate. Notice that obviously markets did not always believe that the exchange rate was going to be fixed, but at time in which they did (for example the period) the Argie rate was locked with the US rate. Potentially this equation can also be used to determine the effects that changes in the interest rate have on the exchange rate (in a flexible exchange rate regime). Consider for example the uncovered interest parity for the dollar/euro i $ i E = log(e E/$ ) log(e e E/$) the theory tells us that in period in which the Dollar interest rate is above the Euro rate we should expect the dollar to depreciate (relative to the Euro) and viceversa. Although this theory works sometimes there are many other times in which the theory fails miserably. Figure 3 shows the Euro and Dollar rate (on the London interbank

9 Exchange rates Argentina Interbank Rate Federal Funds Figure 3: Figure 2: Argentine and US interest rate but its interest rate has to be equal to the Federal Funds Rates that is actually decided by Greenspan. In the picture below we see the Argentina s interbank rate against the Federal Funds rate during the period in which Argentina had fixed exchange rate. Notice that obviously there is a risk premium on the Argentina s rate (this is why Argentina s rate is sometimes above the federal funds rate) but the partity condition is what prevents the Argentina s rate to ever go below the Federal Funds rate.notice that towards the end of the period, as markets were starting to expect a devaluation of the peso, the Argentina s rate shoots up, reflecting

10 Exchange rates Dollars per Euro Interest rate Dollars per Euro Euro interest rate Dollar interest rate Figure 3: The Euro and the Dollar market, LIBOR) together with the Euro dollar exchange rate (the blue line). Notice how in some periods (for example ) the dollar exchange rate behaves in almost exactly the opposite way from what predicted. When, for example US interest rate is above Euro rate the Dollar should be depreciating but instead it appreciates. This suggests that the uncovered interest parity can be used to understand actual or expected exchange rate movements in presence of large interest differentials and large exchange rates swings (which happens often in emerging markets) but it is less useful when the interest rate differentials are smaller and there are potentially many other factors (such as risk premia, financial crises) that affect the fluctuations in exchange rates.

11 Exchange rates 11 Concepts you should know 1. Real and nominal exchange rate 2. PPP 3. Exchange rate regimes 4. Uncovered interest parity